As microprocessors advance in complexity and operating rate, the heat generated in microprocessors during operation increases and the demands on cooling systems for microprocessors also escalate. In some cases, circuit elements at a localized zone on the microprocessor die known as a “hotspot” may raise the temperature at that spot above the average temperature on the die. Thus, it may not be sufficient to keep the average temperature of the die below a target level, as excessive heating at hotspots may result in localized device malfunctions (even if the overall cooling target is met).
Moreover, it may be important that a microprocessor and cooling system be able to withstand cold temperatures (e.g., minus forty degrees Celsius). For example, a Personal Computer (PC) might be exposed to low temperatures while being shipped from a manufacturer, or a laptop computer might be exposed to freezing temperatures when stored in a person's car overnight.